Seismic characterization of inland and coastal sabkhas using VP, VS, seismic anisotropy, and attenuation

Sci Rep. 2025 Nov 27;15(1):44623. doi: 10.1038/s41598-025-29863-w.

Abstract

Sabkhas represent abundant topographic environments along the Arabian Gulf and are increasingly relevant to hydrocarbon exploration and urban development. Their complex geological and hydrogeological settings significantly control near-surface seismic properties, influencing seismic velocity contrasts, attenuation (formula image), and anisotropy. This study presents the first integrated application of P-wave velocity (formula image), S-wave velocity (formula image), formula image ratio, seismic anisotropy, and formula image attenuation analysis in sabkha environments, applied to the mature coastal sabkha of Abu Dhabi (CSAD) and the immature inland sabkha of Jayb Uwayyid (SJUW). Seismic refraction and multichannel analysis of surface waves (MASW) were used to obtain formula image and formula image, compute the formula image ratio, and estimate seismic anisotropy and attenuation. Three distinctive zones were delineated in both sabkhas using the produced tomograms. The shallowest dry zone with formula image​<428 m/s, formula image <261 m/s and ratios of 1-2 with a thickness of 1-5 m, respectively, a transition partially saturated zone with formula image​<1900 m/s, formula image <760 m/s and ratios of 1.5-2.5 extend up to 8 m in CSAD and 6 m in SJUW, a fully saturated zone, extending below the partially saturated zone, is defined by higher velocities (formula image>1900 m/s, formula image>760 m/s) and ratios increasing toward ~2–4.5 with depth. formula image values reach up to 0.05 in both sabkhas, aligning with the hydrological zones, indicating fluid-related attenuation driven by seawater-brine interactions at CSAD and artesian upwelling at SJUW from continental brines. The uppermost parts of CSAD elevated velocities reflect a lithified hardground layer, while its elevated anisotropy marks its complex sedimentary and hydrological evolution. These results highlight the complexity of mature CSAD associated with elevated stratigraphy and hydrological conditions that affect the seismic signal.

Supplementary Information: The online version contains supplementary material available at 10.1038/s41598-025-29863-w.

Keywords: [Formula: see text]; Anisotropy; Multichannel analysis of surface waves (MASW); Near-surface geophysics; Sabkha; Seismic attenuation; Seismic waves.